What is Offset and How Do I Measure It?

Wednesday, August 14, 2013 by Neal O'Neal

Many customers call to ask what their Original Equipment wheel offset is or how they can measure it. The offset of a wheel is the distance from its hub mounting surface to the centerline of the wheel. There are three different types of offset:

  • Zero offset - When the hub mounting surface is even with the centerline of the wheel.
  • Positive offset - When the hub mounting surface is toward the front of the wheel. Positive offset wheels are generally found on front-wheel drive cars and newer rear-wheel drive vehicles.
  • Negative offset - The hub mounting surface is toward the back or brake side of the wheel's centerline. "Deep dish" wheels with large lips are typically have a negative offset.

It's typical for aftermarket wheels to have the offset number stamped on the backside, but that's not always the case with Original Equipment. If you are lucky enough for it to be stamped on the backside it will look like the picture below, with ET representing the offset.

   

When offset is incorrect for a vehicle, handling can be affected and even worse, there may not be enough brake clearance. When the width of the wheel changes, the offset also changes numerically. If the offset were to stay the same while you added width, the additional width would be split evenly between the inside and outside. For most cars, this won't work correctly.

Measuring offset is easier than you may think. If the wheel isn't stamped, simply refer to the diagram on the left. This can be done at home with minimal tools. Although the tire does not have to be dismounted from the wheel to measure, it's much easier if it is.

How do we know what fits your vehicle properly? We do this by knowing every aspect of your vehicle. We measure your vehicle's critical components with sophisticated tools that allow our fitment engineers to create very accurate drawings of these parts. We do the same for the wheels that we offer and then CAD programs to match the wheels to the vehicles.

You can see the complete list of wheels we have available for your vehicle in our Upgrade Garage. Simply enter the specifics on your vehicle’s make, model and year, and our site will display every option we have available that fits properly.

For more information on how we find wheels that are a match for your vehicle, read "How We Know What Fits."

Comments on What is Offset and How Do I Measure It?

Sunday, September 29, 2013 by Adam:
Is a 16 16x5 with a + 30 offset good to go on a 2001 mr2 spyder?any problems with that?
Tuesday, October 1, 2013 by Neal:
I asked our fitment team here and they said it's somewhat aggressive and will require at least a fender roll to clear without rubbing.

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